As q10 mentions above and Merriam Webster confirms, "everywhere that people can perceive" is an entirely valid interpretation of the word "world".

And I don't think of your explanation as a cop-out as you imply. You're not actually misusing an English word here, you're selecting one of multiple definitions based upon your own background, and that's what everyone does when they're reading any language. What I'm trying to figure out is why my students universally (har har) choose the same interpretation as you do. At least half of the people who responded to this survey have a science background or are science enthusiasts, so I think that has colored their responses.